1. Field of the Invention
The present invention relates to a circuit for reducing standby power by converting low power outputted from an AC power supply into DC power, and more particularly, to a standby power redundancy circuit for an electric apparatus which reduces standby power by connecting a microcomputer for exclusive use for a standby power supply to a first side of an AC power supply, and then reducing the power consumption of a main microcomputer of a main body of a set to xe2x80x980xe2x80x99 using the micro computer.
2. Description of the Background Art
FIG. 1 is a block diagram illustrating a standby power redundancy circuit according to conventional art, which is divided into a first side and a second side by a power transmission/switching regulator 103 and a standby transmitter 111. As illustrated therein, the standby power redundancy circuit includes: a standby transmitter 111 receiving AC power from an AC power input unit 101 and converting the same into low voltage; a rectifying unit 110 receiving the converted low voltage and converting the same into DC voltage; a power switch 102 for interrupting (turning on/off) the AC power from the AC power input unit 101; a power transmission/switching regulator 103 receiving the AC power and converting the same into low voltage, in the case that the power switch 102 outputs the AC power; a rectifying unit 104 receiving the converted low voltage, converting the same into DC voltage, and outputting it to a main circuit; diodes 105 and 109 rectifying the DC voltage outputted from the rectifying units 104 and 110; a remote control receiving unit 107 receiving a power-on data outputted from a remote control transmission unit (not shown) upon receipt of the rectified DC voltage and outputting the same; a microcomputer 106 outputting a switching control signal upon receipt of the power-on data; a switch driving unit 108 outputting a switch control signal in order to control the turning on/off of the power switch according to the switching control signal; and a pull-up resistor 106-1 receiving the rectified DC voltage. The operation of them will now be described in detail.
First, the standby transmitter 111 receives AC power outputted from the AC power input unit 101 and converts the same into low voltage.
The rectifying unit 110 converts the converted low voltage into DC voltage, said converted DC voltage is rectified by the diode 109, and then is supplied into the switch driving unit 108, remote control receiving unit 107, microcomputer 106, and pull-up resistor 106-1. In this case, as illustrated therein, since the power switch 102 is in the off state, the voltage is not supplied into the main circuit, and the main body of the set is in the power-off state(standby state).
Here, the standby state is referred to as the state in which the power on/off is possible when a remote control is used in the power-off state of the main body of the set of the main circuit. In other words, since the power switch 102 is in the off state, power outputted from the AC power input unit 101 is not supplied into the main circuit via the power transmitter 103 and the rectifying unit 104.
In this state, when a user transmits power-on data from the remote control (not shown) to the remote control transmission unit 107, the remote control unit 107 transmits the power-on data outputted from the remote control transmission unit to the microcomputer 106. The microcomputer 106 outputs a switching control signal (power on/off signal) to the switching driving unit 108 upon receipt of the power-on data. Here, the microcomputer 106 outputs a variety of control signals (A) and a switching control signal (B). The variety of control signals (A) are used for various control of each element, and the switching control signal (B) is used for controlling the switch driving unit 108.
Afterwards, the switch driving unit 108 outputs a switch control signal (D) in order to control the on/off of the power switch 102 according to the switching control signal.
In this case, when the main body of the set (main circuit) is powered off, e.g., it is in the standby state, the reason why voltage needs to be supplied into the remote control receiving unit 107 and the microcomputer 106 is that the main body of the set has to be powered on, and the timer in the microcomputer 106 has to be operated, in the case that there is a power on/off function operated by the timer.
In this conventional method, since a first side coil of the standby transmitter 111 of the standby state is directly connected to the AC power input unit 101, excitation current always flows in the first side coil. As the result, power is consumed even in the idling condition.
The excitation current is especially large in case of comparison with the current flowing in loads of the standby state (that is, microcomputer, remote control receiving unit, etc.) even in the idling condition. As the result, the AC-DC conversion efficiency is deteriorated, and standby power is consumed by 3xcx9c5W. In this case, the consumption is mostly the excitation current. In addition, in the case that standby power is less than 100 [mW], there is a necessity for considering the pull-up resistor 106-1 of the microcomputer 106 and the power consumption (100 [mW] of the microcomputer 106.
In this way, by using the standby transmitter, the AC-DC conversion efficiency is lowered, and the power consumption is large, e.g. 3xcx9c5 W (mostly the excitation current). In addition, in case of development with a purpose set on standby power of less than 100 [mW], the microcomputer is operated in the standby state. Thus, there occurs a problem that since power of 100 [mW] is consumed, and it is impossible to reduce standby power below 100 [mW].
Accordingly, it is an object of the present invention to provide a standby power redundancy circuit for an electric apparatus which reduces standby power by connecting a microcomputer for exclusive use for a standby power supply to a first side of an AC power supply, and then reducing the power consumption of a main microcomputer of a main body of a set to xe2x80x980xe2x80x99 using the micro computer.
To achieve the above object, in a power circuit having a power switch of a main body of a set of the electric apparatus connected to a first side of an AC power supply and a power transmission/switching regulator of the main body of the set connected to a second side thereof, there is provided a standby power redundancy circuit for an electric apparatus according to the present invention which is characterized in that: a standby power redundancy circuit of the standby state in which the power on/off is enabled using a remote control receives AC power through a reactance device, receives a remote control data from the remote control, connects an exclusive microcomputer for controlling the on/off of the power switch by a switch driving unit to a first side of the AC power supply, and then drive only the exclusive micro computer in the standby state, in the case that the power switch is turned off and the main body of the set is powered off.